`RouteConfigurationInterface::PARAMETER_IDENTIFIER` contains pre-migration `expressive` naming

[boesing]

Bug Report

Q	A
Version(s)	1.0.4

Summary

The route configuration constant RouteConfigurationInterface::PARAMETER_IDENTIFIER contains expressive.cors and thus still contains the pre-migration value which I actually missed when porting to mezzio.

Current behavior

Constant value reflects expressive.cors.

How to reproduce

n/a

Expected behavior

Constant value reflects mezzio.cors.
When the constant value is changed, we should also grab the old route parameter expressive.cors from the configuration until the next major version.